Calcium Hormones: CLINICAL SIGNIFICANCE

Question 1

Most common cause of hypercalcemia combined effects of PTH function

Answer 1

Primary Hyperparathyroidism

Question 2

CAUSED BY: parathyroid adenoma, hyperplasia, carcinoma, hereditary conditions

Answer 2

Primary hyperparathyroidism

Question 3

Unique bone manifestation of PHPT

Bone pain and loss of bone mass

Calcified structures are replaced with fibrous tissue

Bone cyst formation

Answer 3

Osteitis Fibrosa Cystica

Question 4

Hypercalcemia of Malignancy

Underlying cause is generally excessive bone resorption:

With bony metastases (common in hematologic malignancies)
• Direct tumor lysis
• Osteoclast-activating factor by tumor cells
• Lymphokines with osteoclast-potentiating activity (TNF, IL-1)

Question 5

Hypercalcemia of Malignancy

Underlying cause is generally excessive bone resorption:

Without bony metastases
• Humoral hypercalcemia of malignancy
• Over-expression of PTH-related protein (PTHrP) in squamous cell and renal tumors

Question 6

Other Causes of Hypercalcemia

Answer 6

VITAMIN D INTOXICATION (HYPERVITAMINOSIS D):

LITHIUM THERAPY:

HYPERCALCEMIA IN GRANULOMATOUS DISORDERS:

MILK-ALKALI SYNDROME:

Question 7

VITAMIN D INTOXICATION (HYPERVITAMINOSIS D):______ times the normal requirement (> 40,000-100,000 U/d)

LITHIUM THERAPY:____ of patients

Answer 7

40-100

10%

Question 8

unregulated generation of the active form of vitamin D by macrophages in granulomatous tissues (sarcoidosis, tuberculosis

Answer 8

HYPERCALCEMIA IN GRANULOMATOUS DISORDERS

Question 9

increased intake of milk and
absorbable alkali to control gastric acid levels (antacids/calcium carbonate) in patients with peptic ulcers (much less frequent now)

Answer 9

MILK-ALKALI SYNDROME:

Question 10

The calcium-sensing receptor on the
parathyroid cell is mutated

abnormal sensing of the blood calcium by the parathyroid gland and renal tubule

inappropriate secretion of PTH
excessive reabsorption of calcium in the distal renal tubules

Answer 10

Familial Hypocalciuric Hypercalcemia

Question 11

Hallmark: low urinary calcium excretion

Answer 11

Familial Hypocalciuric Hypercalcemia

Question 12

HYPOCALCEMIA

CAUSES:

Answer 12

•hypoparathyroidism
•deficiency of vitamin D

Question 13

Hypoparathyroidism (3 types)

Answer 13

PTH-deficient hypoparathyroidism
PTH-ineffective hypoparathyroidism
PTH-resistant hypoparathyroidism

Question 14

diminished or absent PTH production

Answer 14

PTH-deficient hypoparathyroidism

Question 15

PTH-deficient hypoparathyroidism (2)

Answer 15

Acquired
Inherited

Question 16

PTH-deficient hypoparathyroidism

acquired:

Answer 16

neck surgeries/thyroidectomy

Question 17

PTH-deficient hypoparathyroidism

diminished or absent PTH production

Inherited: (2)

Answer 17

• Defective thymus and parathyroid gland (DiGeorge syndrome)
• hereditary autoimmune syndrome:

Question 18

• Synthesis of biologically inactive
PTH

Answer 18

PTH-ineffective hypoparathyroidism

Question 19

genetic disorder where the body fails to respond to PTH due to defect in
PTH receptor-adenylate cyclase complex

This causes low blood calcium levels and high blood phosphate levels.

Answer 19

Albright’s hereditary osteodystrophy

PTH-RESISTANT HYPOPARATHYROIDISM

Question 20

Pseudohypoparathyroidism

Answer 20

Albright’s hereditary osteodystrophy
PTH-RESISTANT HYPOPARATHYROIDISM

Question 21

Hypovitaminosis D
CAUSES:

Answer 21

• inadequate production of vitamin D
• insufficient dietary supplementation
• inability of Sl to absorb vitamin D
• vitamin D resistance

Question 22

Hypovitaminosis D

EFFECTS:

Answer 22

• disturbances in mineral metabolism (rickets/osteomalacia)

Question 23

Disorders of calcification

Answer 23

Osteomalacia
Rickets

Question 24

• failure to mineralize newly formed organic matrix in bones
• bones become softer

Answer 24

OSTEOMALACIA (adults)

Question 25

• osteomalacia before cessation of growth
• skeletal deformities (bowed legs, rachitic rosary)

Answer 25

RICKETS (children)

Question 26

Rickets vs Osteomalacia

Answer 26

Rickets affects children, causing soft bones and bone deformities.

Osteomalacia affects adults, causing weak bones and increased fracture risk.

Both are due to vitamin D deficiency or impaired calcium absorption.

Question 27

METABOLIC BONE DISEASES

Answer 27

Osteoporosis

Question 28

• reduction in the strength of bone that leads to an increased risk of fractures.
• Loss of bone tissue is associated with deterioration in skeletal microarchitecture.

Answer 28

Osteoporosis

Question 29

Measure or tests for osteoporosis

Answer 29

• Dual Energy X-ray Absorptiometry (DXA)
• Bone Mineral Densitometry:
• CT or MRI

Question 30

• measures grams of calcium per square centimeter of cross sectional area of bone (g/cm2)

Answer 30

Bone Mineral Densitometry

Question 31

HYPOCALCEMIA

Low calcium levels lead to increased nerve excitability

Answer 31

Hypoparathyroidism

Question 32

2 signs of hypoparathyroidism or hypocalcemia

Answer 32

Chvostek sign
Trousseau sign

Question 33

How to test:
1) Place blood pressure cuff around the arm
2) Inflate the cuff for 1-4 mins
3) If hands & fingers go into spasm in palmar flexion = positive

Answer 33

TROUSSEAU’S SIGN

Question 34

How to test:
1) Tap the face just below and in front of the ear
2) If facial twitching occurs of one side of the mouth, nose & cheek = positive

Answer 34

CHOSTEK’S SIGN